Wire rod and wire are ordinarily drawn into a final product matched to the purpose of use. Before conducting the drawing process, however, it is necessary to put the wire rod or wire in a condition for drawing.
As a conventional measure for this, Japanese Patent Publication No. Sho 60-56215 discloses a method for heat treatment of steel wire rod of high strength and small strength variance characterized in that wire rod of steel containing C: 0.2-1.0%, Si&lt;0.30% and Mn: 0.30-0.90% and at austenite formation temperature is cooled between 800.degree. and 600.degree. C. at a cooling rate of 15.degree.-60.degree. C./sec by immersion in fused salt of one or both of potassium nitrate and sodium nitrate fused by heating to a temperature of 350.degree.-600.degree. C. and stirred by a gas.
However, the wire rod of pearlite texture obtained by the heat treatment method described in the aforesaid patent publication involves the problems of ductility degradation during drawing at a high reduction of area and of cracking in twist testing (hereinafter referred to as "delamination").
The object of this invention is to provide high-carbon steel wire rod and wire excellent in drawability and methods of producing the same which advantageously overcome the aforesaid problems of the prior art.